Description: The Carcinogenic Potency Database (CPDB) is described as a "standardized, exhaustive, and easily accessible database of results of chronic, long-term animal cancer test on individual chemicals" that permits investigations into many areas of carcinogenesis research. The core has two goals: to facilitate its use by other investigators, and to use the database to evaluate how animal cancer tests results are used in identifying human carcinogens and setting regulatory priorities. During the past five years, the core has continued to add to and refine the database, and has developed a web site for access to the database, which includes summary tables that can be downloaded by the user. The database includes an estimation of carcinogenic potency, the TD50 for 1,357 chemicals, summarizing the results of 5,240 experiments. Details of each experiment such as strain, sex, and target organ are included. Quality control efforts for data put into the database include independent analysis of the published results on a chemical by at least two people, computer comparison of the authors? analyses, and resolution of any discrepancies. The CPDB includes information on experiments performed in hamsters, nonhuman primates, dogs and rodents. Genotoxicity results from the Salmonella test are also included in the database, and results are linked to the NIEHS database of genotoxicity results on chromosomal aberrations, sister chromatid exchange, mouse lymphoma mutations, and drosophila sex-linked recessive lethal test. Development of the World Wide Web site allows ready access to the CPDB, which includes 60 searchable pages. The Web site is also included in a number of general Web page indices and is linked to a number of other home pages throughout the world. Additional information about effect of diet and micronutrients on carcinogenic potency is accessible through the database. One hundred seventy experiments on 70 food mixtures have been put into the database to date. Analyses using the database have also continued during the past grant period. These analyses have addressed such questions as the usefulness of animal testing, interpretation of results of animals testing, effect of cell death induced by high doses of chemicals on results of animal tests and extrapolation of animal data to humans. Others areas that have been explored are use of the LD50 and the maximally tolerated dose to predict hazard from new chemicals to humans, and investigations into the accuracy of risk calculations for human exposure to pesticide residues. Other lines of investigation are also in progress. Future plans are to develop the database chronologically as new test results are published and inclusion of previously unpublished FDA results on food additives and pharmaceuticals. The database of experiments on micronutrients will be further developed, and new exposure estimates and test results will be used to update risk for specific chemicals. The database will be used in the future to address important issues in carcinogenesis, including interspecies extrapolation, positivity, and mutagenicity. Dietary components and hazards in the workplace will also be ranked using actual exposure estimates.